Boiler and furnace installation



Dec. 15, 1936. w R w D 2,064,098

BOILER AND FURNACE INSTALLATION Filed May 21, 1954 2 Sheets-Sheet lATTORNEYS Dec. 15, 1936. w. R. WOOD V BOILER AND FURNACE INSTALLATIONFiled May 21; 19:54 2 Sheets-Sheet 2- ATTORNEY! Patented Dec. 15, 1936UNITED STATES PATENT OFFICE BOILER AND FURNACE INSTALLATION ApplicationMay 21, 1934, Serial No. 726,678

17 Claims.

The invention is primarily directed toward the combining of boiler partswhich constitute or define a furnace with a horizontal type boiler withdrop section, so as to produce a high capacity installation of simpleand effective design.

Another object of the invention is to provide for common circulation inan arrangement such as the above, without encountering circulationdifficulties.

I am aware that it has been heretofore proposed in installations havingcombustion chambers defined by refractories, to partially line therefractory walls with tubes connected into the circulation of theboiler, as shown for example in the patent to John E. Bell, #1,708,862,issued April 9, 1929. The arrangement of that patent, however, can onlybe operated at certain ratings without encountering circulationdifliculties. I am also aware that to make it possible to operate athigher ratings, it has been proposed to provide independent circulationin the arrangement of the said Bell patent, as disclosed, for instance,in patent l,964,298 issued to Kreisinger and Bell on April 10, 1934.

By my invention, I am enabled to obtain even greater capacities withoutcirculation diificulties notwithstanding that there is commoncirculation for the various boiler parts. In addition, I am also enabledto properly locate the superheater so as to get the desired degree ofsuperheat at the high capacities possible with my installation.

Another object of the invention is to provide such a high capacityinstallation in a simple and effective manner.

Other objects and advantages of the invention will be set forthhereinafter and will be more readily understood in connection with thedescription of the invention.

How the foregoing together with such other objects and advantages as mayhereinafter appear or are incident to my invention are realized isillustrated in preferred form in the accompanying drawings, wherein-Fig. l is a sectional elevation of a boiler and furnace installationconstructed in accordance with my invention.

Fig. 2 is a fragmentary enlarged cross section taken on the line ?.-2 ofFig. 1.

Fig. 3 is an enlarged fragmentary elevational view of the headerconstruction illustrated in Fig. 1.

Fig. 4 is an enlarged fragmentary elevational view, partly broken out,illustrating another form of header construction.

Figs. 5, 6, and 7 illustrate other header modifications; and

Fig. 8 is a fragmentary View illustrating a modification in the downflowconnection to the downof any suitable type for admitting. fuel into the15 combustion chamber, suitable casing'structure D for the installation,and structural work E from which the boiler and associated parts aresus.- pended by means of hangers and brackets, as clearly illustrated inFig. 1. V

The boiler proper A, is of ,the horizontally inclined tube type, and inthis instance comprises two spaced sections or banks of horizontallyinclined tubes 9 and lo, the tubes 9 of the upper bank or section beingconnected at their lower ends into a plurality of downtake or downcomerheaders II, and at their upper ends into a plurality of uptake orupcomer headers l2, and the tubes l 0 of the lower bank or drop sectionbeing similarly connected into a plurality of downcom'er headers l3 andupcomer headers l4.

As illustrated in Fig. 2,1the boiler tubes are arranged in staggeredrelation in spacing such as will give the gas flow needed for efficientheat transfer and the headers are of the sinuous type to accommodate thetubes. However, in instances where the tubes are not staggered, straightheaders may be employed in place ofsuch sinuous headers. I

The downcomer headers ll of the upper bank of tubes 9, are connected tothe water space of the upper steam and water drum [5 of the boiler bymeans of a plurality of rows of downcomer tubes or nipples I6, and theseheaders l l are con: nectedto the downcomer headers 13 of the lower bankof tubes ID by means of a plurality of rows of tubes or nipples IT. Theupcomer headers I4 of the lower bank of tubes are connected to theupcomer headers l2 of the upper bank of tubes by means of a plurality ofrows of tubes or nipples l8, and the upper headers I2 are connected tothe steam space. of the drum l5 by means of a plurality of rows ofdelivery tubes I9. The connecting means illustrated in the form ofdouble rows of nipples l6, l1 and [8 have a free area therethroughfairly closely approximating that through the headers so thatrestriction to flow is minimized. Also, the number of delivery tubes I9is such as to provide free flow. This is particularly desirable withboilers operating under high pressures such as 1200-l400 pounds per sq.in. since in such boilers the nipples are made of smaller diameter so asto have a tube wall thickness which may be satisfactorily rolled.Likewise, as pressures rise a relatively greater downcomer and riserarea is necessary in order to maintain the same fraction steam by volumeleaving the steaming tubes, such as the water wall tubes, for as thepressure rises the density of the steam rises and a greater weight ofsteam and water mixture issues from the water wall tubes. A greaterweight of steam and water mixture in the wall tubes means a relativelygreater volume of water entering the tubes with resultant highervelocities and velocity heads within the wall tubes and downcomers,resulting in greater losses in circulation. These losses must then beoffset by increased riser and/or downcomer areas and as pointed outabove, I accomplish this by increasing the nipple areas.

The furnace or combustion chamber B is defined by steam evaporatingtubes, the front wall being defined by a row of closely spaced uprighttubes 20, the rear wall by a row of closely spaced tubes 2|, and each ofthe side walls by a row of closely spaced tubes 22. These parts, ineffect, constitute a. furnace-shaped boiler. At the top of thecombustion chamber, a row of tubes 23 is provided in advance of thelower bank of tubes 9 of the boiler to minimize clogging of the gaspassage of said bank, and at the bottom, a row of tubes 24 is provided,the spacing being such as to permit gravitating particles to fallthrough to the ash pit below.

The front wall tubes 20 are connected at their lower ends into a lowerdrum or header 25, and at their upper ends into an upper header 26, andthe rear wall tubes 2I are connected at their lower ends into a lowerheader 21 and at their upper ends into an upper header 28. The bottomtubes 24 are connected at one end into the drum or header 25 and at theother end into the header 21, and the top tubes 23 are connected at oneend into the header 25 and at the other end into the header 28. Theheader 28 is connected to the uptake headers Id of the boiler A by meansof nipples 35.

The tubes 22 of the side walls are connected at their lower ends intolower headers 29, which in turn are connected to the lower drum orheader 25 by means of a plurality of supply tubes 30, and these sidewall tubes are connected at their upper ends into upper headers 3| whichin turn are connected to the steam space of the drum I5 by means of aplurality of delivery tubes 32.

It is to be noted that the upper headers 3I of the side Walls arelocated at the upper portion of the boiler A and that the side walltubes 22 preferably extend for the full height of the installation.

Water is supplied to the lower drum or header 25 by means of a pluralityof downcomer tubes 33, located within the casing D and extendingdownwardly from the lower headers I3 of the boiler, and since all of thesteam evaporating tubes referred to have connection with the drum 25, itserves as a common supply means therefor.

The drum 25, due to its low location and to the particular connectionsof the boiler and steam evaporating tubes thereto, serves as a commonblowdown or drain for the entire unit, a Su table blow-off valve 34being provided for this purpose.

It will be seen from the foregoing that the arrangement described isone. calculated togive very high capacities, assuming that there are nocirculation difiiculties and that too much water is not carried into thesteam and water drum.

I have discovered that if I increase the nipple area in the boiler A, Iprovide for adequate circulation, and that the recirculation occurringin the main bank of tubes 9 prevents the carrying over of too much waterinto the drum I5, as will further be described.

The headers of the boiler A as illustrated in Figs. 1, 2, and 3, may beof standard width and depth, the standard depth in an installation ofthe proportions illustrated being 6" as indicated by the dimension linea in Fig. 3. The tubes or nipples I3, II, I8, and 35 are preferably 3/2" in diameter and therefore, since the headers are only 6" in depth, Iincrease the depth at their end portions where the nipples are securedthereto, as indicated at IBa, Ho, and I 8a, so as to obtain sufficientarea for accommodating the double row of nipples with proper ligamentstrength. These enlarged ends may be provided by welding portions I8b tothe headers, as illustrated in Fig. 3.

Referring to Fig. 1, the circulation in the boiler A is from the drum I5downwardly through the tubes or nipples I5 to the headers II, anddownwardly therefrom through the nipples I! to the headers I3. Flow isthen upward through lower rows of the tubes 9 of the upper bank andthrough the tubes I0 of the lower bank to the connected upcomer headersI2 and I I, and thence from the upper headers I2 to the steam space ofthe drum I5 by means of the delivery tubes I9.

The circulation in the steam evaporating tubes of the furnace isdownwardly from the headers I3 through the downcomer tubes 33 to thedrum or header 25. Circulation from the drum 25 is upwardly through thefront wall tubes 20 and top tubes 23 to the header 23 and also upwardlythrough the bottom tubes 24 and rear wall tubes 2i to the header 28.From this header flow is upwardlythrough the nipples 35 and theconnected boiler headers I2 and I4, and from thence to the steam spaceof the drum I5 through means of the delivery tubes I9. The side walltubes 22 receive water from the lower drum 25 by means of the tubes 30and deliver into the steam space of the upper drum I5 by means of thetubes 32.

In connection with the circulation, it is pointed out that since thetubes I0, the tubes 2|, and the tubes 20 and 23 deliver into the headersI4, and since these headers in turn deliver into the headers I2 intowhich also the tubes 9 deliver, it would normally be expected that therewould be so much water in the mixture in the headers I2 that too muchwater would be carried into the drum I5; particularly since thecirculation through the tubes 20, 2i and 23 is relatively very rapid,producing a tendency to elevate water in the headers I2. I have found,however, that the recirculation which occurs in the main or upper bankof tubes overcomes this difiiculty, there be ing a substantial downflowthrough the upper rows of the tubes of this bank. The amount ofrecirculation occurring in the main bank is somewhat dependent upon thenumber of rows of tubes employed in such bank. The requisite number canbe readily determined for any given installation. In the drawings, themain bank is fourteen rows of tubes high.

As will be seen from Fig. l, I locate a superheater S in the verticalspace between the upper and lower tube banks so that it is in a locationwhere the desired degree of superheat will be obtained. I am enabled toso locate the superheater because of employing a drop section in theboiler connected to the upper section by means such as the nipplesspaced apart sufficiently to permit of insertion and removal of thesuperheater tubes. In this connection it will be noted that there areonly a few rows of tubes in the lower bank for the reason that theradiant heat tubes of the combustion chamber absorb a large quantity ofheat, which makes it advantageous to locate the superheater as shown.

In Fig. 4, I have illustrated a modification in which in addition toproviding increased nipple area, I also provide increased header area byenlarging the headers. In instances where the size and spacing of thetubes of the boiler, in order to secure efficient heat transfer in theboiler, is such that increased header area cannot be obtained byincreasing the width of the headers, I obtain the extra area byincreasing the depth of the headers, in which case, as shown in Fig. 4,ample area is provided for the double row of connecting nipples. In highpressure boilers where smaller tubes are employed narrower headers thanstandard may be used to give closer tube spacing and the extra area maybe obtained by making the headers of greater depth. While I have onlyillustrated the downcomer headers Ila and |3a in Fig. 4, it will beunderstood the upcomer headers may be of similar construction.

The construction of the headers of. the boiler A, as shown in Figs. 5to? inclusive, differs from that of the other figures in that interiorpartitions or dividing walls are employed. As illustrated in Fig. 5, theheaders are divided into inner and outer separated compartments orchambers 39 and 40 by the partitions 4|. At the upper portion of theupper headers I2, I provide cross portion 43 (see Fig. 9) so that thechambers 39 deliver to the lower rows of tubes l9 and the chambers 49 tothe upper rows. As illustrated in Fig. 6, the partitions are providedwith apertures in line with the tubes and with the apertures in theouter walls of the header for inserting and securing the tubes in place.These aper tures are provided with closures such as plugs 42.

In the modifications illustrated in'Fig. 6 and '7, I employ crosspartitions 44 in the inner chambers 39 of the headers l3 and M of thelower bank of tubes l0. These cross partitions are located directlyabove the lowermost row of tubes of the bank l9, and the lower portionsof the upright or dividing partitions 4| of the upcomer headers M arecut away so that the tubes of the bottom row communicate with the outerchambers 40 of the headers. At the downcomer headers 13, however, theupright partitions 4| extend for the full height of the headers. It willbe seen that in this arrangement, therefore, the front wall tubes 20 areconnected with the lower row of tubes of the bank In, and that these inturn deliver into the outer chambers M! of the upcomer headers 14, fromwhich delivery is to the steam and water drum.

In some instances, it may be desirable to construct the upcomer headersM as shown in Fig. 5, and the downcomer headers as shown in Fig. '7, inwhich case the front wall tubes 20 would 'deliver into the innerchambers 39 of the upcomer headers l4 through the medium of the bottomrow of tubes of the bank [-0, and the bottom tubes 24, and the rear walltubes 1| would deliver into the outer chamber 40 of said upcomerheaders.

In the modification illustrated in Fig. 8, I have shown the downcomertubes IBa as being of a capacity sufliciently large to adequately supplyboth the boiler A and the wall tubes.

The various headers may be of .welded construction with the dividingpartitions welded in place, or they may be one piece with the'partitionsin the form of plain strips dropped in through an open top.

It is pointed out that the divided headers are particularly useful wherethe water walls are of. relatively low height in which case segregationof the column of steam-water mixture rising from the walls to the steamand water drum of the boiler, is desirable in order to maintain a lightcolumn of mixture in the risers to the drum so as to stimulate the wallcirculation.

Assuming that the tubes of the boiler banks are 4 inches in diameter,the tubes of a horizontal row would be spaced apart approximately 7inches and the rows of tubes from centre line to centre verticallyconsidered would be spaced apart approximately Gf ths inches.

It is to be observed that through the practice of my invention, aninstallation of very simplified character is provided because thedowncomer tubes 33 and the rear wall tubes 2| may be aligned with theheaders of the boiler A while still providing effective circulation inthe system. These tubes as well as the side wall tubes and in fact allof the connections referred to, are all located within the casing Dwhich provides a very compact arrangement and permits of great plainnessand simplicity of the casing. Furthermore, I obtain through myarrangement, the advantages of effective circulation throughout thesystem without the necessity of employing the customary complicatedarrangement of tubes located outside the casing, it being noted thatthere are no outside downcomers or upcomers and that the downcomer tubes33 and front wall tubes 20 are located in a common wall of. the casing.

In explanation of the above, it is pointed out that while arrangementsuch as shown in the above mentioned Kreisinger and Bell patent avoidcirculation difficulties, the number of tubes required as downcomers andupcomers greatly increases the cost of the installation and alsopresents difficulties in the design, because most of them have to belocated outside of the boiler and furnace setting where they interferewith access doors, structural members of thesetting, burner or stokerparts, and the like. In addition, in such arrangements, many of thetubes have to be bent for the most part with individualbends, which ofcourse, adds materially to the cost as do the complications arising inconnection with the propersh-eathing of. the tubes.

I claim: a

1. The combination with a boiler having an upper and a drop tube sectioneach comprising a plurality of horizontally inclined tubes and downcomerand upcomer headers into which the tubes are connected, of a combustionchamber associated with said boiler, steam evaporating tubes in thechamber constituting walls of the combustion space thereof, downcomermeans connecting said steam evaporating tubes to the boiler for supply,said steam evaporating tubes being connected to deliver into the upcomerheaders of the drop section of the boiler, and means connecting saidupcomer headers to the upcomer headers of the upper section having afree area therethrough approximating that through the headers whereby tominimize restriction to flow.

2. The combination with a boiler having an upper and a drop tube sectioneach comprising a plurality of horizontally inclined tubes and downcomerand upcomer headers into which the tubes are connected, of a combustionchamber associated with said boiler, steam evaporating tubes in thechamber constituting walls of the combustion space thereof, downcomermeans connecting said steam evaporating tubes to the boiler for supply,said steam evaporating tubes being connected to deliver into the upcomerheaders of the drop section of the boiler, and means connecting the saidupcomer headers to the upcomer headers of the upper section, saidconnecting means having a cross-sectional area approximating thecross-sectional area of the upcomer headers whereby to provide freedelivery from the tubes of the drop section and from the steamevaporating tubes into said upcomer headers of the drop section, andfrom said upcomer headers of the drop section to the upcomer headers ofthe upper section.

3. The combination with a boiler having an upper and a drop tubesectioneach comprising a plurality of horizontally inclined tubes and downcomerand upcomer headers into which the tubes are connected, of a combustionchamber associated with said boiler, steam evaporating tubes in thechamber constituting walls of the combustion space thereof, downcomermeans connecting said steam evaporating tubes to the boiler for supply,said steam evaporating tubes being connected to deliver into the upcomerheaders of the drop section of the boiler, and a plurality of meansconnecting said upcomer headers of the drop section to the upcomerheaders of the upper section, said connecting means having acrosssectional area approximating the cross-sectional area of theupcomer headers whereby to provide free delivery from the tubes of thedrop section and from the steam evaporating tubes into said upcomerheaders of the drop section, and from said upcomer headers of the dropsection to the upcomer headers of the upper section, said connectingmeans being spaced apart to permit removal of superheater tubestherebetween, and a superheater in the space between sections.

4. The combination with a boiler having an upper and a drop section eachcomprising a plurality of horizontally inclined tubes and downcomer andupcomer headers into which the tubes are connected, of a combustionchamber associated with said boiler, steam evaporating tubes in thechamber constituting walls of the combustion space thereof, said steamevaporating tubes having downcomer and upcomer connection to thedowncomer and upcomer headers respectively of the drop section, andmeans connecting the headers of the drop section to the headers of theupper section having a free area therethrough approximating that throughthe headers whereby to minimize restriction to flow.

5. The combination with a boiler having an upper and a drop section eachcomprising a plurality of horizontally inclined tubes and downcomer andupcomer headers into which the tubes are connected, of a combustionchamber associated with said boiler, steam evaporating tubes in thechamber constituting walls of the combustion space thereof, said steamevaporating tubes having downcomer and upcomer connection to thedowncomer and upcomer headers respectively of the drop section, anddouble rows of nipples connecting the headers of the drop section to theheaders of the upper section.

6. In a high capacity boiler and furnace installation the combination ofa boiler of the horizontally inclined tube type and a furnace havingsteam evaporating tubes constituting walls of the combustion spacethereof, said boiler having an upper section and a drop section eachcomprised of upright downcomer and upcomer headers, and horizontallyinclined tubes connecting the headers, a plurality of rows of nipplesconnecting the upcomer and downcomer headers of the sections together,and downcomer means leading from the downcomer headers of the dropsection to said steam evaporating tubes, said steam evaporating tubesbeing connected for delivery into the upcomer headers of the dropsection.

'7. The combination with a boiler having a steam and water drum, anupper tube section, a drop tube section therebelow, each sectioncomprising a plurality of horizontally inclined tubes and downcomer andupcomer headers into which the tubes are connected, of a combustionchamber associated with said boiler, steam evaporating tubes in thechamber constituting walls of the combustion space thereof, downcomermeans connecting said steam evaporating tubes to the downcomer headersof the drop section for supply, said steam evaporating tubes beingconnected to deliver into the upcomer headers of the drop section, meansconnecting the downcomer headers and the upcomer headers of the sectionstogether, having a free area therethrough approximating that through theheaders, downcomer means from the water space of the steam and waterdrum to the downcomer headers of the upper section, having a free areatherethrough approximating that through the headers, and a plurality ofdelivery tubes leading from the upcomer headers of the upper section tothe steam and water drum, said delivery tubes having a combined freearea approximating the cross-sectional area of said upcomer headers toprovide free delivery to the drum; whereby to minimize restriction toflow.

8. The combination with a boiler having a steam and water drum, aplurality of substantially horizontal tubes, and downcomer and upcomerheaders into which the tubes are connected, of a combustion chamberassociated with said boiler, and steam evaporating tubes defining theupright walls of the combustion chamber, all of said steam evaporatingtubes having downcomer connection with said downcomer headers of theboiler, and the steam evaporating tubes of at least two of said wallshaving upcomer connection with said upcomer headers of the boiler, andsaid headers being of a capacity greater than necessary to provideeffective circulation in such boiler, the excess capacity being such asto provide eifective circulation in the steam evaporating tubes withoutinterfering with the boiler circulation, the remaining of said steamevaporating tubes being connected for delivery to said steam and waterdrum.

9. In a high capacity boiler and furnace installation, the combinationof a boiler of the horizontally inclined tube type and a furnace havingsteam evaporating tubes lining its upright walls, said boiler having asteam and water drum, a plurality of upright downcomer and upcomerheaders, and horizontally inclined tubes of standard spacing connectedat their ends into said headers, downcomer means leading from thedowncomer headers of the boiler to said steam evaporating tubes, thesteam evaporating tubes of a pair of opposite walls being connected fordelivery into said upcomer headers, and the upcomer headers being ofstandard Width to accommodate the standardly spaced boiler tubes, but ofa depth considerably greater than standard, whereby the circulation ofthe boiler and-of the steam evaporating tubes is adequately provided forwithout interference of one with the other, and the tubes of theremaining pair of opposite walls being connected for delivery to thesteam and water drum.

10. In a high capacity boiler and furnace installation, the combinationof a boiler having horizontally inclined boiler tubes and a plurality ofupright downcomer and upcomer headers into which said boiler tubes areconnected, and a combustion chamber below said boiler having uprightsteam evaporating tubes at a wall thereof, upright downcomer tubesleading from said down-- comer headers and connected to supply saidsteam evaporating tubes, said downcomer tubes and steam evaporatingtubes being arranged in rows in close parallel relationship and inapproximate alignment with said downcomer headers, means connecting saidsteam evaporating tubes to deliver into the upcomer headers of theboiler, upright steam evaporating tubes at the opposite wall of thecombustion chamber in alignment and delivery connection with saidupcomer headers, and means connecting said last mentioned wall tubes toreceive Water supply from the boiler.

11. In a high capacity boiler and furnace installation, the combinationof a boiler having horizontally inclined boiler tubes and a pluralitylationship and in approximate alignment with said downcomer headers,means connecting said steam evaporating tubes to deliver into theupcomer headers of the boiler, upright steam evaporating tubes at theopposite wall of the combustion chamber in alignment and in deliveryconnection with said upcomer headers, a lower header into which thelower ends of the said last mentioned tubes are connected, and tubesextending across the lower portion of the combustion chamber connectingthe first mentioned header means and said second mentioned lower header.

12. In a high capacity boiler and furnace installation, the combinationof a boiler having horizontally inclined boiler tubes and a plurality ofupright downcomer and upcomer headers into which said boiler tubes areconnected, and a combustion chamber below said boiler having uprightsteam evaporating tubes at a wall thereof, upright downcomer tubesleading downwardly from said downcomer headers, a lower header intowhich the lower ends of said steam evaporating and downcomer tubes areconnected, said tubes being arranged in rows in close parallelrelationship and in approximate alignment with said downcomer headers,an upper header into which the upper ends of said steam evaporatingtubes are connected, upright steam evaporating tubes at the oppositewall of the combustion chamber in alignment with said upcomer headers, alower header into which the lower ends of the said last mentioned tubesare connected, spaced tubes extending across the lower portion of thecombustion chamber connecting the first and second mentioned lowerheaders, an upper header into which theupper ends of the secondmentioned steam evaporating tubes are connected, means connecting saidlast mentioned upper header with the upcomer headers of the boiler, andspaced tubes extending-across the upper portion of the combustionchamber connecting said first and second mentioned upper headers.

13. In a high capacity boiler and furnace installation, the combinationof a boiler of the horizontally inclined tube type comprising aplurality of upright front downcomer and rear upcomer headers andhorizontally inclined tubes connected at their ends into 'said headers,casing structure enclosing said boiler, a furnace below said boilerhaving its front and rear walls in approximate alignment with the frontand rear upright headers of the boiler respectively, upright steamevaporating tubes lining said walls and exposed to the radiant heat ofthe furnace, downcomer tubes at and within said front wall connected tothe downcomer headers of the boiler and to said wall tubes for supplyingsaid wall tubes with water from the boiler, and said wall tubes beingconnected to deliver into the upcomer headers of the boiler.

14. In a high capacity boiler and furnace installation, the combinationof a boiler of the horizontally inclined tube type comprising aplurality of upright front downcomer and rear upcomer headers andhorizontally inclined tubes connected at their ends into said headers,casing structure enclosing said boiler, a furnace below said boilerhaving its front and rear walls in approximate alignment with the frontand rear upright headers of the boiler respectively, upright steamevaporating tubes lining said walls and exposed to the radiant heat ofthe furnace, downcomer tubes at and within said front wall connected tothe downcomer headers of the boiler and to said wall tubes forsup-plying said wall tubes with water from the boiler, said wall tubesbeing connected to deliver into the upcomer headers of the boiler,upright steam evaporating tubes lining the side walls of the furnace andexposed to the radiant heat thereof, means connecting said side walltubes to receive water from the downcomer headers of the boiler, andmeans connecting said side wall tubes to deliver into the boiler, all ofsaid tubes being confined inside the walls of the furnace and the casingof the boiler.

15. In a high capacity boiler and furnace installation, the combinationof a boiler of the horizontally inclined tube type and a furnace havingsteam evaporating tubes ranged upright at its side, front, and rearwalls, said boiler having a plurality of downcomer and upcomer headersand horizontally inclined tubes connected at their ends into saidheaders, and an upper steam and water drum into which the boiler tubesdeliver, downcomer means leading downwardly from the downcomer headersof the boiler, means connecting said downcomer means with the lowerportions of said steam evaporating tubes, the steam evaporating tubes ofthe front and rear walls being connected for delivery into the upcomerheaders of the boiler, and means connecting the steam evaporating tubesof the side walls for delivery into the steam and water drum of theboiler.

16. In a high capacity relatively high pressure boiler and furnaceinstallation the combination of a boiler of the horizontally inclinedtube type comprising a plurality of upright front downcomer and rearupcomer headers and horizontal- 1y inclined boiler tubes connectingthem, a furnace below said boiler having its front and rear walls linedwith upright steam evaporating tubes, partition means dividing saiddowncomer boiler headers into inner and outer chambers, downcomer tubesleading from said outer chambers to said wall tubes, partition meanssub-dividing said inner chambers into upper and lower chambers, andbeing so located that the lowermost boiler tubes connect into the lowerchambers and that the remaining ones connect into the upper chambers,the partition means in said rear upcomer headers being arranged so thatsaid lowermost boiler tubes deliver into the outer chambers of saidheaders, said front walltubes being connected to deliver into the bottominner chambers of the boiler downcomer headers, and said rear nectedinto two circulation circuits of substantially equal resistance to flow,one of said circuits being connected for delivery to said steam andwater drum and the other of said circuits being connected for deliverywith said upcomer headers of the boiler.

WILFRED ROTHERY WOOD.

